This invention relates to a method and apparatus for treating materials to be treated, such as semiconductor wafers or the like, for effecting a reduced pressure epitaxial vapor phase growth or etching at a pressure different from the atmospheric pressure and/or in an atmosphere for the purpose of manufacturing semiconductor devices for example, and more particularly, a multichamber sheet-after-sheet type treating method and apparatus for effective treating.
A prior art multichamber sheet-after-sheet type treating apparatus is generally constructed such that a plurality of sheet-after-sheet type radial treating chambers are connected through gate valves to the periphery of a platform of a central chamber or a preparatory chamber.
The interior of the platform is maintained at a pressure or filled with an atmosphere different from the ambient air so that when the treating chamber is opened to the platform, the inside of the treating chamber and materials to be treated would be spoiled with external substances (which will be called particles hereinafter) such as oxygen and dust in the air.
Charging and discharging of the materials to be treated into and out of the treating chamber are performed through an inlet/outlet port connected to the platform via a gate valve and through the platform. More particularly, after inserting the material to be treated into the inlet/outlet port by opening it to the surrounding air, the inlet/outlet port is closed to interrupt the communication with the surrounding air, to make the interior of the inlet/outlet port to be same pressure or atmosphere. Thereafter, the inlet/outlet port and the platform are intercommunicated. Under this condition, a material not yet treated conveyed into the inlet/outlet port is admitted into respective chambers by robots in the platform. At the same time, the material which has been treated in respective treating chambers is returned to the inlet/outlet port.
According to the multichamber sheet-after-sheet type treatment of this type, respective treating chambers are not opened to the surrounding air, and since the platform is always maintained at a predetermined pressure or filled with a predetermined atmosphere, the treatment in the treating chambers can be performed accurately and efficiently so that there is an advantage of effecting at a high efficiency the sheet-after-sheet type treatment accompanying a problem of treating ability. For this reason, as the radius of the wafer of a semiconductor wafer becomes large, in the field of the semiconductor manufacturing apparatus where the batch treatment must be changed to the sheet-after-sheet type treatment, multichamber sheet-after-sheet type treating apparatus have became important.
Multichamber sheet-after-sheet type treating apparatus are classified into a first type wherein the same treatment is performed in parallel in respective treating chambers and a second type wherein different treatments according to a series of manufacturing processes are performed continuously. Respective types are the same in that accurate treatments are made efficiently.
In a prior art multichamber sheet-after-sheet type treating apparatus, for the purpose of increasing treating efficiency, a plurality of materials to be treated is generally inserted into an inlet/outlet port at a time, the inlet/outlet port is opened when the treatments in the treating chambers of all materials thrown into the inlet/outlet port is completed for simultaneously taking out the treated materials, and then the materials to be treated next are again inserted into the inlet/outlet port. More particularly, although the treatments in respective treating chambers are of the sheet-after-sheet type treatment, the insertion and extraction at the treated materials from the inlet/outlet port is of the batch treating type. For this reason, the inlet/outlet port generally contains an elevator which is moved in the vertical direction and supports a plurality of materials to be treated and which is stacked in multiple stages.
However, when the elevator is contained in the inlet/outlet port, the volume of the inlet/outlet port would become large so that it is either necessary to use a large capacity exhaust pump or a long time is necessary for exhausting and for returning to atmospheric pressure, thereby decreasing a percentage of working. Moreover, as a result of throwing in many materials to be treated, the quantity of particles brought into the inlet/outlet port increases and the removal of the particles from the inlet/outlet port is not complete. Moreover, it is not only necessary to prevent the generation of dust as the elevator is moved up and down but also the number of rejects of materials to be treated increases when faults occur in the treating chamber or the like.
Furthermore, it is necessary to interrupt the treatment in the treating chamber when the inlet/outlet port is opened to the atmosphere for exchanging the materials to be treated. For the purpose of exchanging the materials to be treated between the inlet/outlet port and the atmosphere, it is necessary to increase the pressure in the inlet/outlet port to that of the atmosphere, and after replacing the atmosphere in the inlet/outlet port to an atmosphere that can be opened to the surrounding air, the inlet/outlet port is opened to complete exchange of the materials to be treated. Thereafter when the inlet/outlet port is closed again, it is necessary to make the pressure in the inlet/outlet port equal to that of the platform or to the same atmosphere. The interruption time necessary for this operation increases with the volume in the inlet/outlet port.
For this reason, the time required for exchanging the materials to be treated between the inlet/outlet side and the external air causes a great decrease in the operating efficiency of the apparatus so that it is a recent tendency to further increase the number of materials thrown into the inlet/outlet port at the same time.